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TY - CONF AU - Wu, A.D. AU - Chu, Q.W. AU - Guo, H. AU - He, Y. AU - Huang, S.C. AU - Li, C.L. AU - Pan, F. AU - Song, Y.K. AU - Tan, T. AU - Xiong, P.R. AU - Yue, W.M. AU - Zhang, S.H. AU - Zhao, H.W. ED - Michel, Peter ED - Arnold, André ED - Schaa, Volker RW TI - The Cryostat Results of Carbon Contamination and Plasma Cleaning for the Field Emission on the SRF Cavity J2 - Proc. of SRF2019, Dresden, Germany, 30 June-05 July 2019 CY - Dresden, Germany T2 - International Conference on RF Superconductivity T3 - 19 LA - english AB - The field emission effect is the mainly limitation for the operating of SRF cavities in higher gradient with stability. In this paper, the experiments were performed to evaluate the impact of the carbon contaminants and plasma cleaning on the performance of SRF cavity. Contamination mechanism was classified into cryogenic adsorption with weak strength and chemical deposition with strong strength. For the weak strength condition, the methane was injected into the SRF cavity during vertical test to make a cryogenic adsorption layer on the inner surface of the cavity. The results revealed that the performance of SRF cavity degraded by methane physical adsorption, but the performance can be recovered by thermal cycle the cavity to 300K and pump methane out. For the strong strength condition, the chemical deposited dirty layer of carbon contamination was produced by using of Ar/CH₄ mixed PECVD method, and the SRF cavity performance was deteriorated by the severe field emission. Finally, carbon deposited cavity was treated by the Ar/O2 plasma, and its results revealed that the field emission removed greatly and the gradient was increased. PB - JACoW Publishing CP - Geneva, Switzerland SP - 1038 EP - 1040 KW - cavity KW - plasma KW - SRF KW - experiment KW - cryogenics DA - 2019/08 PY - 2019 SN - 978-3-95450-211-0 DO - doi:10.18429/JACoW-SRF2019-THP064 UR - http://jacow.org/srf2019/papers/thp064.pdf ER -